What kind of LED is this ?!

[Exie]

Hi folks,

I just had the backlight go on my car stereo, it's a 10yr old unit, but I'd like to repair it if I can. I've poped the front panel off, and there was an LCD screen there. I took the metal casing of the screen off, and theres a Sanyo LC75850 chip underneath, on the ends of this, there seem to be 2 globes, this is all I need to replace I hope.

Any idea what sort they are ? I assume they are 12v, could I replace them with some small ultra-white 15000MCD LED's I've got ? these ones kinda look special though, any ideas what should ask for down at Jaycar ?

 

[justDIY]

those are miniature incandescent bulbs - most likely 12v as you suspect

you could replace them with inverted cone aka 360 degree leds, just solder in one lead of the led, and leave the other out, so you can solder a resistor to it, and to some other point on the pcb which provides power or ground (depending on whats easiest)

 

[Exie]

.. that makes sense, LED's been kinda directional wouldnt light it up much. I dont think theres room to fit a bezel in their, the LCD panel that goes on top kind has a round hole that the globes sit in.

I might whip down to Jaycar this arvo and pick up some SL2685's and see if that'll do the job.

Thats for the tip.

 

[Sceadwian]

LED's are used in this kind of configuration frequently, they usually rely on the plastic bezel to distribute the light evenly and it doesn't take much, there has to be SOME kind of reflector or refraction element even if they are bulbs.

 

[Exie]

Thanks, I ended up just going with globes as the only LED's I had were 5mm ones and they were a bit big.

The repair went well, but it isnt quite as bright as it was <shurg> .. no big deal though.

Thanks for the adivce, muchly appreaciated.

 

[djtaylor]

FWIW, I have just had to replace a bulb on my wifes car stereo. Interestingly the PCB was screen printed for LED's but the board was fitted with bulbs. I initially tried a 12V bulb but it was very dim leading me to suspect that the voltage was already dropped.

As a bit of fun, I consulted with my wife because my choice of LED's at the time was a bit limited to either high intensity which literally illuminated the interior of the car when the radio was on, or a rainbow RGB LED.

She chose the funky RGB LED shown here, the colours are actually much more vivid than the video shows and do more colours

www.nodomainname.co.uk/pimpmyride.avi

David.

 

[Hero999]

Couldn't you just use a high intensity LES and use a big series resistor so it isn't so bright?

Either way, the RGB LED looks cool.

 

[djtaylor]

To be honest, I wouldn't use an ultrabright LED anyway, mine was seriously bright, way too bright with one. Even the RGB LED is bright. Fitting a resistor might be awkward since the bulb/LED chosen will have to sit flush with the PCB and would mean cutting tracks.

I put a LED in instead of a bulb because I didn't want a repeat of desoldering 50+ pins from my LCD panel if the bulb blew again.

David.